From 24558c2f40583632dfa741079e9cd61fbaab1a54 Mon Sep 17 00:00:00 2001
From: Matt Whitaker <matt@acmwhitaker.co.uk>
Date: Fri, 27 May 2022 17:03:21 +0100
Subject: [PATCH] Add extra args to prepare-commit-msg

---
 pre_commit/commands/hook_impl.py | 18 +++++++++++++++++-
 pre_commit/commands/run.py       | 12 +++++++++++-
 2 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/pre_commit/commands/hook_impl.py b/pre_commit/commands/hook_impl.py
index f315c04de..71b884905 100644
--- a/pre_commit/commands/hook_impl.py
+++ b/pre_commit/commands/hook_impl.py
@@ -76,6 +76,8 @@ def _ns(
         remote_name: str | None = None,
         remote_url: str | None = None,
         commit_msg_filename: str | None = None,
+        commit_msg: str | None = None,
+        commit_sha: str | None = None,
         checkout_type: str | None = None,
         is_squash_merge: str | None = None,
         rewrite_command: str | None = None,
@@ -90,6 +92,8 @@ def _ns(
         remote_name=remote_name,
         remote_url=remote_url,
         commit_msg_filename=commit_msg_filename,
+        commit_msg=commit_msg,
+        commit_sha=commit_sha,
         all_files=all_files,
         checkout_type=checkout_type,
         is_squash_merge=is_squash_merge,
@@ -202,8 +206,20 @@ def _run_ns(
     _check_args_length(hook_type, args)
     if hook_type == 'pre-push':
         return _pre_push_ns(color, args, stdin)
-    elif hook_type in {'commit-msg', 'prepare-commit-msg'}:
+    elif hook_type in 'commit-msg' or hook_type == 'prepare-commit-msg' and \
+            len(args) == 1:
         return _ns(hook_type, color, commit_msg_filename=args[0])
+    elif hook_type == 'prepare-commit-msg' and len(args) > 1:
+        if (len(args) == 2):
+            return _ns(
+                hook_type, color, commit_msg_filename=args[0],
+                commit_msg=args[1],
+            )
+        else:
+            return _ns(
+                hook_type, color, commit_msg_filename=args[0],
+                commit_msg=args[1], commit_sha=args[2],
+            )
     elif hook_type in {'post-commit', 'pre-merge-commit', 'pre-commit'}:
         return _ns(hook_type, color)
     elif hook_type == 'post-checkout':
diff --git a/pre_commit/commands/run.py b/pre_commit/commands/run.py
index 37f989b57..9109a7603 100644
--- a/pre_commit/commands/run.py
+++ b/pre_commit/commands/run.py
@@ -147,6 +147,7 @@ def _run_single_hook(
         diff_before: bytes,
         verbose: bool,
         use_color: bool,
+        extra_hook_args: tuple[str, ...] = (),
 ) -> tuple[bool, bytes]:
     filenames = classifier.filenames_for_hook(hook)
 
@@ -189,7 +190,10 @@ def _run_single_hook(
             filenames = ()
         time_before = time.time()
         language = languages[hook.language]
-        retcode, out = language.run_hook(hook, filenames, use_color)
+        retcode, out = language.run_hook(
+            hook, filenames + extra_hook_args,
+            use_color,
+        )
         duration = round(time.time() - time_before, 2) or 0
         diff_after = _get_diff()
 
@@ -282,9 +286,15 @@ def _run_hooks(
     retval = 0
     prior_diff = _get_diff()
     for hook in hooks:
+        extra_args: tuple[str, ...] = ()
+        if args.commit_msg:
+            extra_args = (args.commit_msg,)
+        elif args.commit_msg and args.commit_sha:
+            extra_args = (args.commit_msg, args.commit_sha)
         current_retval, prior_diff = _run_single_hook(
             classifier, hook, skips, cols, prior_diff,
             verbose=args.verbose, use_color=args.color,
+            extra_hook_args=extra_args,
         )
         retval |= current_retval
         if retval and (config['fail_fast'] or hook.fail_fast):